1. Field of the Invention
This invention relates to an adhesive tape feeding apparatus, more particularly to an adhesive tape feeding apparatus, which can feed automatically a predetermined length of a free end portion of a tape roll therefrom after the latter is cut off.
2. Description of the Related Art
A conventional tape feeding apparatus has been disclosed in U.S. Pat. No. 3,690,531, which can feed automatically a predetermined length of a free end portion of a tape roll therefrom after the latter is cut off. However, the aforesaid conventional tape feeding apparatus has a relatively complicated structure that results in an increased manufacturing cost.
The object of this invention is to provide an adhesive tape feeding apparatus, which has a relatively simple structure.
According to this invention, an adhesive tape feeding apparatus includes a base, an adjustment unit, and a push unit. A tape roll is disposed rotatably on a rear end portion of the base. When a motor is activated, a free end portion of the tape roll is fed from a front end portion of the base by means of a feeding roller set. The free end portion of the tape roll can be forced to press against a blade under tension, which is fixed on the base, so as to be cut by the blade, thereby moving a push unit to press a follower arm of the adjustment unit against a microswitch. Then, the microswitch activates the motor to rotate a cam wheel in such a manner that the cam wheel presses the follower arm against the microswitch. The cam wheel has an outer periphery which is shaped so as to release the follower arm automatically from the cam wheel and the push unit after the cam wheel rotates by a predetermined angle, thereby feeding a predetermined length of the free end portion of the tape roll, which can be changed by adjusting the adjustment unit between a first-length position and a second-length position.
In one embodiment, the outer periphery of the cam wheel has a short linear portion, a short circular arc portion, a long linear portion that is longer than the short linear portion, and a long circular arc portion that is longer than the short circular arc portion. Each of the long and short linear portions interconnects the long and short circular arc portions. The follower arm is spaced apart from the center of the cam wheel at a distance which is larger than that between the center of the cam wheel and either of the long and short linear portions when the adjustment unit is disposed at the second-length position, and which is larger than that between the center of the cam wheel and the long linear portion and smaller than that between the center of the cam wheel and the short linear portion when the adjustment unit is disposed at the first-length position.